This invention relates to novel, water-soluble, stable salts of antimony (V) glycol esters, useful as flame retardants.
Various antimony compounds have been used heretofore as flame retardants. The most commonly used compound is antimony trioxide. When used as a flame retardant for fabrics, antimony trioxide has the drawback of being insoluble in water or other common solvents, and it thus cannot be introduced within the fiber. Antimony trioxide applied to the outside of the fiber is subjected to mechanical wear and abrasion and is readily lost from the surface, unless special binders are used. These binders, such as ethylenevinyl acetate copolymer, make the fabric stiff and they are suitable only for use in tents, tarpaulins, etc.
Antimony (V) salts, such as antimony pentachloride, are decomposed by water with the liberation of the corresponding acid, such as hydrochloric acid. They are, therefore, unsuitable for use as flame retardants in many situations. Various antimonates, such as sodium antimonate or potassium antimonate, also are known; however, their low solubility in water limits their use. Antimony (V) esters also are known. Some of the esters are highly sensitive to moisture, decomposing readily in moist air. Several esters of antimony (III) and antimony (V) are disclosed in U.S. Pat. No. 3,031,425 to be useful flame retardants. While conventional antimony (V) esters are soluble in organic solvents and can be incorporated into organic polymers, they are less suitable for use in hydrophilic fibers or fabrics, such as cotton, which always contain water within the fibers.
There is a need, therefore, for water-stable, flame retardant antimony compositions which can be introduced into hydrophilic materials and can be insolubilized therein.